1. Field of the Invention
This invention relates to a resistance welding apparatus for welding divided small thin segments to a blade base to form a rotary saw blade. More particularly the invention relates to an electrode clamp apparatus whereby the segments are pressed against the blade base to ensure uniform contact between the segments and the base during the welding apparatus.
2. Background of the Invention
A saw blade 0 for use as a concrete cutting tool is, as shown in FIGS. 1A and 1B, for instance, generally prepared by forming radial shallow slitted grooves 2 at equal intervals in the circumferential direction of a discoidal blade base 1. Small hard pieces of segments 3 equivalent to the edges of the saw blade are joined to the peripheral surfaces thus divided and formed between the adjoining slitted grooves.
High-carbon steel is normally used for the blade base 1 because of its high resistance to shock and fatigue. On the other hand, wear resistant sintered metal including diamond as a constituent is used for the segments 3 which form the edge of the saw blade. To weld the segments to the blade base, brazing with a relatively high melting point has conventionally been employed.
The conventional brazing method employs silver filler mental with comparatively high melting point. However, due to the frictional heat generated during dry cutting, the brazed material at the joint where the segment contacts the blade base deteriorates as the temperature exceeds the melting point of the filler metal. As a result, the mechanical strength of the joint is lost, which causes the segment to peel off. In addition to the above drawbacks, is the high level of skill required in the manufacturing process and the high cost of the brazing material.